As Barack Obama and John McCain jockey to claim the reformer's mantle, each has touted his own campaign finance record while impugning that of his opponent, and both have misrepresented aspects of the arcane world of campaign finance to fit their respective claims. It’s not always easy to tell the “new” politics from the old brand without a scorecard.

Here, then, is Politico’s effort to set the record straight on five myths about campaign cash in 2008:

527s are a major factor

The independent groups have not been big players in the race, though they could quickly reshape the landscape — as they did in 2004 — in the four months remaining until Election Day.

Obama, however, has been wielding the threat of the thus-far inconsequential 527s to tarnish McCain’s reform bona fides, rally his own donors and justify his reversal of a pledge to participate in the public financing system.

“We’ve already seen that [McCain] is not going to stop the smears and attacks from his allies running so-called 527 groups, who will spend millions and millions of dollars in unlimited donations,” he said in a video posted on his website.

Though both candidates have decried the influence of 527s, there’s not a whole lot either can do to rein them in, since campaign finance laws prohibit candidates from coordinating with 527s.

Case in point: Obama has asked his supporters not to contribute to outside groups, but one of the most active independent organizations to date has been the California-based PowerPAC, which funds ads and voter registration drives intended to benefit Obama.

In blasting Obama for breaking his promise to accept public financing, McCain reiterated that he would participate in the system, thereby limiting his general election spending to the $84 million grant of taxpayer cash.

No one doubts that McCain will spend every cent of that, but he’s also raised $55 million in private contributions and spent $32 million from March through May on what has effectively been a general election campaign, including ads targeting Obama.

Under federal election rules, McCain’s general election campaign won’t officially begin until he accepts the Republican nomination at the party’s convention in early September. So he’ll be able to continue raising and spending private contributions until then.

McCain broke campaign finance law in the primary

Team Obama is accusing McCain of breaking the rules of the primary election public financing system, and the Democratic National Committee has filed a Federal Election Commission complaint — and a lawsuit to compel FEC action — on the matter.

But the law on the subject is far from clear. The FEC’s tradition of granting flexibility in the public financing system — not to mention its penchant for deadlocking on partisan issues — make it unlikely it will find McCain broke the law.

At issue is whether McCain committed himself to participating in the primary election public financing system late last year, when his then-struggling campaign made a complicated pact with a bank. In order to secure a loan, McCain indicated that if he withdrew from the public funding system, but didn’t come within 10 percentage points of winning the New Hampshire primary, he would reapply for public funds and use them to pay back the loan.

McCain did win New Hampshire and his fundraising picked up when he began to pull away from the GOP pack afterwards, so he never used the public funds. A day after the Super Tuesday primaries, he informed the FEC he was withdrawing from the public funding system, which limits participants’ spending.

In response, then-FEC Chairman David Mason requested more information about the tricky loan agreement and asserted that the campaign needed the commission’s approval before it could withdraw.

But owing to a partisan stalemate in the Senate over nominations, the six-seat commission lacked the four members necessary for a quorum until late last month.

In the time it took the Senate and the Bush administration to reach an agreement over nominees, McCain paid back the loan, but also exceeded the spending limits, though most election law experts expect the reconstituted FEC to overlook that, since McCain had asked to withdraw beforehand.

Even Mason — a Republican whose nomination was withdrawn in what some saw as retribution for questioning McCain’s loan — predicted in late January that the commission would be accommodating. Mason told Politico that the FEC has “some flexibility in addressing the particular situations candidates may find themselves in and — currently — the commission's ability or inability to take particular actions. We'll have to address any particular situations when and as they actually occur.”

Whether that flexibility will extend to the underlying question — whether McCain’s loan committed him to public financing — is an open question.

But there’s little reason to expect that one of the commission’s three new Republican members would side with the three Democratic members to produce the four votes necessary for a finding against McCain.

Lobbyists and PACs are big players in presidential politics

Obama has encouraged this idea to tout his refusal to accept contributions from federal lobbyists and political action committees and criticize McCain’s unwillingness to follow suit.

But lobbyists and PACs historically have not been major contributors to presidential campaigns, and this cycle has been no different.

According to the Center for Responsive Politics, McCain through May had received $1.1 million from PACs and $686,000 from employees of lobbying firms. That’s less than two percent of his $110 million total haul (LED) for the campaign.

Likewise, the fundraising landscape won’t be substantially altered by Obama’s announcement last month that the DNC under his leadership would also cease accepting contributions from lobbyists or PACs.

From the beginning of the race through the end of May, the DNC raised only $2.3 million from PACs and employees of lobbying firms — good for about 3 percent of its $77 million total haul, according to a Politico analysis of data from the FEC and the center.

The Republican National Committee’s haul over the same period was $147 million, of which $2 million, or about 1.4 percent, came from PACs and employees of lobbying firms or their spouses.

The lobbying firm tally only includes contributions from lobbyists employed by lobbying firms, not directly by companies or associations. Their contributions are tougher to track, though it’s unlikely they would substantially boost these tallies.

That’s because lobbyists and PACs haven’t generally been major contributors in this or other presidential campaigns. Their contributions are more effectively directed to members of Congress who decide the fate of the legislation around which D.C.’s influence industry revolves.

Hillary Clinton’s debt is a pressing concern

This idea has been encouraged both by Hillary Clinton and by Obama — albeit for different reasons.

Clinton owed $22.5 million at the end of May — $12.2 million of which she’d loaned to her own campaign. She wants to pay back as much of the debt as quickly as possible, since it typically gets harder to raise money as the election fades further into the past.

Obama, meanwhile, has urged his big-money donors to contribute to Clinton’s debt retirement because he’s trying to create goodwill with Clinton’s top supporters, from whom he hopes to reap contributions. In a symbolic gesture, he and his wife Michelle each wrote maximum $2,300 checks to Clinton.

But Clinton is unlikely to recoup much — if any — of her personal loan, and there’s no deadline for her to pay back the other $10.3 million of her debt, which stems mostly from unpaid bills to vendors.

She has until the end of the Democratic convention to pay herself back in full. After that, her campaign can only pay her $250,000 plus interest (her campaign reported owing $26,000 in interest at the end of May).

As for the vendor debt, it’s common for big campaigns, particularly losing ones, to let unpaid bills linger, sometimes for years.

About $8 million of Clinton’s debt is owed to consultants, pollsters and others who regularly work on campaigns, and understand that such delays are part of the very profitable political industry — and are unlikely to cause legal or political headaches by demanding prompt payment. More than half of that debt — $4.6 million — is owed to close ally and longtime pollster Mark Penn.

Don’t be surprised to see those bills linger if Clinton doesn’t quickly raise enough to pay off her vendor debt.